//------------------------------------------------------------------------------
#endif
decode.h 解压函数主函数
#ifndef __DECODE_H__
#define __DECODE_H__
//------------------------------------------------------------------------------
#include
#include
#include
//------------------------------------------------------------------------------
VOID out_code( WORD code ,PBUFFER_DATA buffer,PLZW_DATA lzw,PSTACK_DATA stack)
{
WORD tmp;
if( code < 0x100 )
{
stack->lp_stack[ stack->index++ ] = code;
}
else
{
stack->lp_stack[ stack->index++ ] = lzw->lp_suffix[ code ];
tmp = lzw->lp_prefix[ code ];
while( tmp > 0x100 )
{
stack->lp_stack[ stack->index++ ] = lzw->lp_suffix[ tmp ];
tmp = lzw->lp_prefix[ tmp ];
}
stack->lp_stack[ stack->index++ ] = (BYTE)tmp;
}
while( stack->index )
{
if( buffer->index == BUFFERSIZE )
{
empty_buffer(lzw,buffer);
}
buffer->lp_buffer[ buffer->index++ ] = stack->lp_stack[ --stack->index ] ;
}
}
//------------------------------------------------------------------------------
VOID insert_2_table(PLZW_DATA lzw )
{
lzw->lp_code[ lzw->code ] = lzw->code;
lzw->lp_prefix[ lzw->code ] = lzw->prefix;
lzw->lp_suffix[ lzw->code ] = lzw->suffix;
lzw->code++;
if( lzw->code == ((WORD)1<cur_code_len)-1 )
{
lzw->cur_code_len++;
if( lzw->cur_code_len == CODE_LEN+1 )
lzw->cur_code_len = 9;
}
if(lzw->code >= 1< {
re_init_lzw(lzw);
}
}
//------------------------------------------------------------------------------
WORD get_next_code( PBUFFER_DATA buffer , PLZW_DATA lzw )
{
BYTE next;
WORD code;
while( buffer->by_left < lzw->cur_code_len )
{
if( buffer->index == BUFFERSIZE )
{
load_buffer( lzw->h_sour, buffer );
}
next = buffer->lp_buffer[ buffer->index++ ];
buffer->dw_buffer |= (DWORD)next << (24-buffer->by_left);
buffer->by_left += 8;
}
code = buffer->dw_buffer >> ( 32 - lzw->cur_code_len );
buffer->dw_buffer <<= lzw->cur_code_len;
buffer->by_left -= lzw->cur_code_len;
return code;
}
//------------------------------------------------------------------------------
VOID do_decode( PBUFFER_DATA in, PBUFFER_DATA out, PLZW_DATA lzw, PSTACK_DATA stack)
{
WORD code;
WORD tmp;
while( in->index != in->top )
{
code = get_next_code( in ,lzw );
if( code < 0x100 )
{
// code already in table
// then simply output the code
lzw->suffix = (BYTE)code;
}
else
{
if( code < lzw->code )
{
// code also in table
// then output code chain
tmp = lzw->lp_prefix[ code ];
while( tmp > 0x100 )
{
tmp = lzw->lp_prefix[ tmp ];
}
lzw->suffix = (BYTE)tmp;
}
else
{
// code == lzw->code
// code not in table
// add code into table
// and out put code
tmp = lzw->prefix;
while( tmp > 0x100 )
{
tmp = lzw->lp_prefix[ tmp ];
}
lzw->suffix = (BYTE)tmp;
}
}
insert_2_table( lzw );
out_code(code,out,lzw,stack);
lzw->prefix = code;
}
}
//------------------------------------------------------------------------------
VOID decode( HANDLE h_sour, HANDLE h_dest )
{
LZW_DATA lzw;
BUFFER_DATA in ;
BUFFER_DATA out;
STACK_DATA stack;
BOOL first_run;
first_run = TRUE;
lzw_create( &lzw ,h_sour,h_dest );
buffer_create( &in );
buffer_create( &out );
stack_create(&stack );
while( load_buffer( h_sour, &in ) )
{
if( first_run )
{
lzw.prefix = get_next_code( &in, &lzw );
lzw.suffix = lzw.prefix;
out_code(lzw.prefix, &out, &lzw , &stack);
first_run = FALSE;
}
do_decode(&in , &out, &lzw, &stack);
}
empty_buffer( &lzw,&out);
lzw_destory( &lzw );
buffer_destory( &in );
buffer_destory( &out );
stack_destory( &stack);
}
#endif